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Subject[PATCH v3 5/6] percpu: factor out pcpu_check_chunk_hint()
Date
Factor out the pcpu_check_chunk_hint() helper, which will be useful
in the future. The new function checks if the allocation can likely
fit the given chunk.

Signed-off-by: Roman Gushchin <guro@fb.com>
---
mm/percpu.c | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index e20119668c42..357fd6994278 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -306,6 +306,26 @@ static unsigned long pcpu_block_off_to_off(int index, int off)
return index * PCPU_BITMAP_BLOCK_BITS + off;
}

+/**
+ * pcpu_check_chunk_hint - check that allocation can fit a chunk
+ * @chunk_md: chunk's block
+ * @bits: size of request in allocation units
+ * @align: alignment of area (max PAGE_SIZE)
+ *
+ * Check to see if the allocation can fit in the chunk's contig hint.
+ * This is an optimization to prevent scanning by assuming if it
+ * cannot fit in the global hint, there is memory pressure and creating
+ * a new chunk would happen soon.
+ */
+static bool pcpu_check_chunk_hint(struct pcpu_block_md *chunk_md, int bits,
+ size_t align)
+{
+ int bit_off = ALIGN(chunk_md->contig_hint_start, align) -
+ chunk_md->contig_hint_start;
+
+ return bit_off + bits <= chunk_md->contig_hint;
+}
+
/*
* pcpu_next_hint - determine which hint to use
* @block: block of interest
@@ -1065,15 +1085,7 @@ static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits,
struct pcpu_block_md *chunk_md = &chunk->chunk_md;
int bit_off, bits, next_off;

- /*
- * Check to see if the allocation can fit in the chunk's contig hint.
- * This is an optimization to prevent scanning by assuming if it
- * cannot fit in the global hint, there is memory pressure and creating
- * a new chunk would happen soon.
- */
- bit_off = ALIGN(chunk_md->contig_hint_start, align) -
- chunk_md->contig_hint_start;
- if (bit_off + alloc_bits > chunk_md->contig_hint)
+ if (!pcpu_check_chunk_hint(chunk_md, alloc_bits, align))
return -1;

bit_off = pcpu_next_hint(chunk_md, alloc_bits);
--
2.30.2
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